Upgrade Ruby (and likely gem deps) #1004
Description
The Ruby version we use (3.0.6) is out of date.
Our hosting service (Heroku) used for our.terrastories.app is deprecating the currently used infrastructure stack (heroku-20) on which TS is hosted, and requires a newer Ruby version (3.1.6 at minimum) for the next one (heroku-24). Per Heroku: "Apps using Heroku-20 do not receive security updates and can no longer be built. Please upgrade your apps to a newer Heroku stack."
We can't deploy new updates (like #1002) on Heroku until we upgrade Ruby.
The current stable version of Ruby is 3.4.4. We should probably update to the latest version. I don't know if that will cause any gems to fail, so might need to update some gem deps as well to meet the minimum requirement of unblocking us from pushing updates.